Illumination apparatus



United States Patent ILLUMINATION APPARATUS Wilfred Henschel,Pleasantville, N .Y.

Application April 3, 1957, Serial No. 650,401

4 Claims. (Cl. 2401.2)

This invention relates to illumination apparatus and relates moreparticularly to an improved lighting means for airport taxi-waysalthough its use is not restricted to any particular locality. Since itis particularly advantageous for lighting airport taxi-ways, theinvention will be particularly described in this connection.

' In the prior art, airport taxi-ways have been equipped with markerlights defining their boundaries, each consisting of an incandescentlamp enclosed in a glass globe mounted on a conduit stem with a conicalskirt. Such lights have relatively low visibility, are expensive tomaintain and operate because of the short life and low efficiency of theincandescent lamp and constitute a hazard to the propellers of aircrafthitting them.

Efforts have been made to use fluorescent instead of incandescent lightsfor the purpose but they have not been satisfactory for the reasons thattheir light output drops to intolerably low values at low temperatures,that in some cases high voltages make servicing and relamping dangerous,and that the units become inoperative if inundated by flood. Furtherobjections reside in the fact that they have an inherently non-uniformlight distribution and their high power consumption and the largecircuit capacity required make their application on existing lightingcircuits both diflicult and expensive. The design of the illuminatingdevice or marker light of the present invention overcomes the foregoingdifficulties.

An important object of the present invention is the provision of alighting apparatus for this purpose which provides a larger light sourcewith increased visibility under all operating conditions than doexisting airport taxi-way marker lights.

Another important object of the invention is to provide an improvedmarker light unit for airports which is waterproof so that even if thelanding field is flooded with water up to or even above the top of theunit it will still operate and use of the field may be resumed after theflood without servicing the lights.

A further important object of the invention is to provide a fluorescentlighting fixture whose light output is substantially unaffected by lowtemperatures, this being accomplished by the combination of an outertransparent cylinder or envelope forming a general housing for thestructure, and an inner, closed tubular housing or envelope of smallerdiameter which receives and encloses the lighting element. The innertubular envelope and the outer housing efiectively insulate the lightingunit and assure satisfactory operation at its lowest temperature even atlow power consumption.

Another important object of the invention is to provide a lightingfixture in which the aforesaid inner tubular housing supports the uppersocket support and socket while the socket in turn supports andenergizes the lamp. This arrangement prevents electric shock to aworkman replacing the lamp since the lamp is accessible only when it isde-energized, while the socket support is at ground potential and thesocket is of such design that the workman cannot accidentally touch thelive contact.

Another important object of the invention is to provide a lightingfixture which will not damage a whirling propeller if it by chanceshould hit the light. To this end, the parts above the base, includingthe inner and outer plastic housings, the fluorescent tube and the othermembers are easily shattered or displaced by impact of the propeller andthe cost of replacement is far less than the cost of repair to thepropeller or replacement by a new propeller. The light of the presentinvention is also so designed that upon being bowled over on coming incontact with a landing wheel or other moving object, the connector ofthe fixture lead will separate and thereby automatically short circuitthe secondary of a series transformer supplying power to it, eliminatingthe troublesome additional distortion of the alternating current wave ofa series circuit when one or more transformer secondaries areopencircuited and which may result in excessive and damaging voltagesand cause unsatisfactory starting or operation of the remaining lightson the circuit.

Yet another important object of the invention is to provide a fixturewhich with its transformer or ballast can be installed on existingseries or multiple lighting circuits without change in the circuits andcan, if desired, be replaced by a mere substitution of conventionalincandescent lights and their transformers or ballasts.

The lighting unit of the present invention would usually be arranged foruse in a vertical position and substantially at ground level but it maywith minor modification be placed in a horizontal position for certainapplications or even in an inverted position or at an angle to thevertical. Also it may be mounted on fences, roof tops or at any otherelevation or location. It may also be used with or without minormodification as a route marker or taxi guidance sign for airports orother locations, as a light for the home, for marine use, and for alldecorative or utilitarian lighting purposes anywhere.

In the drawings:

Fig. 1 is a perspective view of the lighting unit of the presentinvention.

Fig. 2 is a central vertical section taken through the unit, the sectionbeing taken on line 22 of Fig. 1.

Fig. 3 is a horizontal section taken on line 3-3 of Fig. 2.

Fig. 4 is a broken section taken on line 4-4 of Fig. 3.

Fig. 5 is a broken side elevation showing the lower end of the innertubular envelope.

Fig. 6 is a diagram of the circuit employed.

The lighting unit 10 of the present invention is mounted on a suitablesupport. If it is to be used as an airport taxi-way marker light it maybe mounted on a fracture joint such as a conventional type of frangiblecoupling shown at 11 and having a threaded section 12 at its lower endwhich is received in a threaded opening (not shown) in a cover plate 13formed of metal. The cover plate which is electrically grounded ispositioned substantially at ground level on an electrical handhole 14usually formed from metal and concrete. The handhole may have a metalliner 15 having a horizontal flange 16 at its Patented Oct. 6, 19592,9o7,ses

upper end and the cover plate is secured thereto by bolts 20. If thecover plate is formed of non-metallic material a separate grounding wiremay be supplied.

A circular base plate 21 may be formed as an aluminum casting and it hasa central opening 22 (Fig. 4) for wires indicated at 23 which arepreferably in the form of a two-conductor cord, the opening beingdefined by a downwardly extending nipple section 24 which is received inthe upper tubular unthreaded portion of the breakable coupling and issecured therein by set screws 25. At the lower end of this tubularportion there is an annular groove 26 generally V-shaped in crosssection which forms a thin frangible annular connecting portion which isstrong enough to support the unit under conditions of gale or evenhurricane but which is readily broken when the unit is struck by amoving object.

Means are provided on the base for detachably mounting in rigid relationan inner tubular envelope forming a housing for the lamp unit. As shownthere is aligned with nipple 24 on the upper surface of plate 21 anarcuate boss or pedestal 30 having an opening 31 at one side thereof.The pedestal has blind threaded openings 32 for screws which mount adisc 33 on its upper surface which supports the lower socket 34 which isof the type which is spring loaded so that the lamp is raised intoposition for convenient ready removal when metal cap 41 is removed. Thepedestal is of such diameter as to receive in close fitting engagementthe transparent inner tubular envelope 35 which is secured thereto byscrews 36. The tube is cut away at 37 (Fig. to form an opening for thewires and this opening is aligned with opening 31 in the pedestal.instead of the screws a bayonet joint may be used as the mounting meansor this may be a screwthreaded arrangement.

An illumination unit such as a straight fluorescent tube 38 is receivedand supported at its lower end in socket 34 and an upper socket 40 issecured to a metal cap 41 carried at the upper end of tube 35. For thepurpose of securing the cap in place it may be formed with bayonet slots42 which received pins 43 secured to the upper end of tube 35.

The dome-shaped outer envelope 44 is closed at its upper end as shown at45 and may have a larger diameter at its lower end. It may usually beformed from transparent colored plastic material. The particular colordepends upon its use and application. It may be frosted on its innersurface to cause a diffusion of light over the entire inside surface andexpanding the light, as it were,

rom a line source to a columnar source. The dome can be made in avariety of ways, such as being formed in one piece, or it may be formedin two identical halves with two opposed vertical cemented seamsextending down the sides. There should be no holes or other openings inthe seams or elsewhere in the dome since it should be watertight andairtight.

Means for securing the dome to the base may comprise a ring 46 which iscemented or formed around the lower margin of the dome forming anattaching flange and this ring is received in flat relation on aresilient sealing gasket 50 cemented to a recessed annular seat 51formed on the periphery of base 21. A split ring 52, U-shaped in crosssection, is used to secure the flange to the base. Ears 53 at the endsof the ring receive a tightening screw 54 to draw the terminals of thering together to securely mount the dome on the base. Alternatively, thedome may have a screw thread at the lower end received on a thread onthe base, or a trunk type clamping ring may be used.

Lead-in wires 23 and the clamp which secures them to the base are notshown in Fig. 2 but one of these wires is connected with a wire 55 whichis connected with lower socket 34. This wire is also grounded as shownin the circuit diagram of Fig. 6. Accordingly the lower socket isgrounded at all times so that the lamp is dead during replacement. Theother lead-in wire is connected with a wire 56 of a shielded cable, thewire being connected at its opposite end to upper socket 40. The metalshield 60! of this cable is connected at its lower end with a groundingboss 61 formed on the base. The upper end of the shield is connected at63 to cap 41. The other bosses 62 may be used to mount any other desiredcomponents on the base.

A transformer 64 is preferably placed within the elec trical handhole. Aseparable connection is shown at 65 and there may be associated withthis connection a pair of spring contacts 66 which become connectedtogether if the lighting unit is bowled over, thus short circuiting thetransformer secondary.

While there have been described herein what are at present consideredpreferred embodiments of the invention, it will be obvious to thoseskilled in the art that many modifications and changes may be madetherein without departing from the essence of the invention. It istherefore to be understood that the exemplary embodiments areillustrative and not restrictive of the invention, the scope of which isdefined in the appended claims, and that all modifications that comewithin the meaning and range of equivalency of the claims are intendedto be included therein.

What I claim is:

l. A lighting structure for airstrips and the like for mounting atground level on an electrical handhole, said structure including a basecomprising a generally flat disc having an opening, a pedestal extendingupwardly therefrom, a frangible coupling secured to the base formounting the same on the electrical handhole, a transparent dome-shapedhousing forming an outer envelope and provided at its lower end with anannular flange mounted on the base, a clamping ring securing the housingthereon in sealed relation, an inner vertical transparent tubularenvelope rigidly secured on the outer periphery of the pedestal and alower socket secured atop the pedestal, a second socket at the upper endof said tubular envelope, an elongated lighting tube in the latterenvelope and whose opposed terminals are received in the sockets, andmeans connecting the sockets with a source of electrical energy.

2. A lighting structure for airstrips and the like for mounting on acover plate at ground level on an electrical handhole, said structureincluding a base comprising a generally flat disc having a centralopening, a nipple extending downwardly from the opening and an arcuatepedestal extending upwardly therefrom, a frangible coupling mounted onthe cover plate and receiving said nipple, a transparent domeshapedhousing forming an outer envelope and secured at its lower end in sealedrelation on the base, an inner vertical transparent tubular envelopesecured on the outer periphery of the pedestal, a tubular lighting tubein the latter envelope, and means connecting the opposite ends of thelighting tube with a source of electrical energy.

3. A lighting structure for airstrips and the like for mounting on acover plate at ground level on an electrical handhole, said structureincluding a base comprising a generally flat disc having a centralopening and an arcuate pedestal extending upwardly from the opening, afrangible coupling mounted on the cover plate and supporting said base,a transparent dome-shaped housing forming an outer envelope and providedat its lower end with an annular flange supported on the base, an innervertical transparent tubular envelope secured on the outer periphery ofthe pedestal and a lower socket secured atop the pedestal, a removablecap at the top of the inner envelope and an upper socket securedthereto, a fluorescent tube in the latter envelope and whose opposedterminals are received in the sockets, and means connecting the socketsthrough the nipple and coupling to a source of electrical energy.

4. A lighting structure for airstrips and the like for mounting on acover plate at ground level on an electrical handhole, said structureincluding a base comprising a generally flat disc having a centralopening defined by a nipple extending downwardly from the opening and anarcuate pedestal extending upwardly therefrom, a frangible couplingmounted on the cover plate and receiving said nipple, a transparentdome-shaped housing forming an outer envelope and provided at its lowerend with an annular flange supported on the base, a resilient sealinggasket between the flange and the base, an inner vertical transparenttubular envelope secured on the outer periphery of the pedestal and alower socket secured atop the pedestal, a removable cap at the top ofthe inner envelope and an upper socket secured thereto, a fluorescenttube in the latter envelope and whose opposed terminals are received inthe sockets, and means connecting the sockets through the nipple andcoupling to a source of electrical energy. 1

2,166,393 Crossley July 18, 1939 2,186,079 Rolph Jan. 9, 1940 2,489,686Suter Nov. 29, 1949 2,501,437 Cline et a1 Mar. 21, 1950 2,764,670 DusenSept. 29, 1956 OTHER REFERENCES Illuminating Engineeiing- Development ofa Gaseous Tube Directional Taxi-Way Marker Light, M. S. Gilbert (pp.603-605).

